1. Field of the Invention PA1 2. Description of the Prior Art PA1 a spout (1) provided with a dispensing guide (11) communicating with a dispensing valve (2); PA1 a thin nozzle (10) provided within the nozzle or dispensing guide (11) and having a smaller dispensing port (10a) whose bore d is not more than 0.5 mm; and PA1 a larger dispensing port (1a) having a bore b of 0.8 to 3 mm and a length c of not less than 5 mm, formed within the dispensing guide (11) farther ahead in the dispensing direction than the thin nozzle (10).
The present invention relates to a dispensing structure for aerosol containers, and more specifically to a dispensing structure for aerosol containers, designed for satisfactory dispensing of aerosol while controlling the discharge rate of the aerosol contained within.
The basic configuration of an aerosol container to which a dispensing structure according to the prior art is applied will be described below with reference to the accompanying FIG. 4.
In the aerosol container according to the prior art, a cup (20) having a dispensing valve (2) at the center is fitted hermetically to the aperture of a container (3) by clinching the cup body (21) together with the curled lip (31) of the container (3).
The dispensing valve (2) is formed by inserting a spring (25) through the aperture of a housing (23), fitting a valve stem (24) having a prescribed inside diameter (e.g. .phi. 0.33 mm) into the housing (23) with a prescribed gap in-between, and hermetically caulking the housing (23) into the central part of the cup (20) via a gasket (22), with the top part of the valve stem (24) protruding out.
The housing (23) has a lower port (23') communicating with the inside of the container (3), and the valve stem (24) has an upper port (24') communicating with the inside of the housing (23). The lower port (23') is always in communication with the container (3), while the upper port (24') is usually blocked by the gasket (22) as the valve stem (24) is pressed upward by the spring (25).
The top end of the valve stem (24) protruding out of the cup (20) closely communicates with a pipe-shaped spout (1).
The spout (1) has an integrated insert (11a) in the central part of a pipe-shaped dispensing guide toward its base end as well as a cap section (13) integrated with the outer circumference of this insert (11a). The top end of the valve stem (24) is inserted into the insert (11a), and the cap section (13) is fitted around the seamed edges (21) and (31) of the container (3).
The spout (1), so shaped that the dispensing guide (11) protruding upward from the cap section (13) is bent in a dogleg form, is designed to have a bore (f) of, for instance, 1.5 mm and a length (g) of 19 mm.
The aerosol to be filled into the container (3) consists of a solution prepared by blending various ingredients and an aerosol propellant, consisting of a liquefied gas having a prescribed gas pressure. Therefore, the aforementioned aerosol container is given a prescribed internal pressure by the gas pressure of the aerosol propellant.
The aerosol container is so configured that when a manipulative piece (13a) on the cap section (13) of the spout (1) is pressed, the valve stem (24) moves downward, and the concurrent descent of the position of the upper port (24') causes the container (3), the housing (23) and the spout (1) to communicate with one another and thereby the aerosol filling the container (3) to be dispensed from the spout (1).
It is usual for an aerosol container of the type described above to be fitted with a nozzle (12) having a small diameter port (12a) (of about 0.5 mm in bore) at the tip of the spout (1), as illustrated in the accompanying FIG. 5, as a means to control the discharge rate of the aerosol per unit length of time.
The spout (1) shown in FIG. 5, because the bore at its tip is smaller than that of the spout shown in FIG. 4, can better control the discharge rate of aerosol. However, the spout (1) illustrated in FIG. 5 involves the following problems.
First, as the formation of the smaller dispensing port (12a) at the tip of the spout (1) results in a corresponding smaller cross-sectional area of the tip, the dispensing pressure at the tip is greater than at the tip of the spout (1) shown in FIG. 1 when the aerosol is dispensed. Therefore, when the aerosol is dispensed from the smaller dispensing port (12a) externally (into the atmosphere), the vaporization of the propellant contained in the aerosol is suddenly accelerated, resulting in an increase in the quantity of fine particles with possible hazard to the safety of humans who happen to inhale the mist, depending on the recipe of the aerosol.
Second, the finer particles mean that the dispensed aerosol will scatter over a greater area, and contaminate and/or wastefully involve unintended parts with the scattering aerosol.
Third, where the aerosol is characterized by a sense of coolness the heat of vaporization of the propellant enables its user to feel, the acceleration of its vaporization invites the problem of weakening this sense of coolness.
An object of the present invention is to provide a dispensing structure for aerosol containers, which can control the discharge rate of aerosol and ensure satisfactory and safe dispensing of the aerosol while preventing the particle size of the dispensed aerosol from becoming too fine and its excessive scattering which too fine particles would entail.
Other objects and features of the invention will become apparent to those skilled in the art from the following description.